The present invention relates to a manually operated ergonomic wheelchair and in particular to a wheelchair designed to enable, during operation, the user to maintain an upright posture, moreover encouraging his or her proportioned physical development. Said wheelchair is also particularly suitable for sporting use, even on rough or sloping ground.
Known wheelchairs currently available on the market can be divided into two major categories according to the type of operating system, namely wheelchairs with an electrical or manual operating system. In this second category, which includes the present invention, it can been seen how the more traditional type of manual wheelchair operating system, i.e. that consisting of two metal rings fixed laterally to the wheels which the user can operate by pushing directly with his or her hands, has remained basically the only one in widespread use, thanks to its practical and economical nature, ease of use and minimal bulk. In contrast to these advantages, an operating system of this type does however have important functional disadvantages, from the point of view of the user, relating to the very poor ergonomics of the movements which the user has to perform for its operation. An upright position of the user during the pushing phase is in fact only possible (but definitely not facilitated) during limited transit in an apartment, due to the fact that, on account of the short travel paths and low rolling friction, it is possible to restrict the movement of the hands gripping the pushing rings to a few centimetres. In all other cases--and in particular in outdoor uses, and in the sporting uses which are becoming increasingly widespread among young disabled persons--acceptable power of movement and travel speed can only be achieved at the cost of considerably lengthening the gripping travel length of the hands on the rings, for example up to at least a quarter of the entire circumference of the rings. In order to achieve this long gripping travel length, the user must necessarily adopt an extremely curved position of the torso, with negative effects both on the potential thrust, which is small compared to the full capability of the user in an upright position, and on the permanent deformation of the torso caused by constant adopting of this posture.
Alternative solutions to the traditional one, also of the type with jointed levers or with a chain transmission, have been proposed in the art, without however any of them, due to problems both of high cost and mechanical complexity, having ever found favour with users and, as a result, appreciable growth on the market.